Novel Fire Retardant Compounds

ABSTRACT

Compounds with fire extinguishing properties having the formula: 
     
       
         
         
             
             
         
       
     
     wherein R 1  is —CR 5 R 6 R 7  or —CR 5 R 6 CR 8 R 9 R 10  as well as fire extinguishing units including one or more of the compounds.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. application Ser. No.16/126,746, filed Sep. 10, 2018, which is a divisional of U.S.application Ser. No. 14/753,760, filed Jun. 29, 2015, the disclosure ofeach of which is incorporated herein by reference in its entirety.

BACKGROUND OF THE INVENTION Field of the Invention

This invention concerns novel halogen containing compounds and fireextinguishing units including one or more fire extinguishing compounds.

Description of the Art

Halon 1301 is the predominant fire extinguishing agent used on aircraft.Halon 1301 is currently a banned substance with few exceptions. One suchexception is its use as an aircraft fire extinguishing agent. However,even with this exception, new fire extinguishing compounds are neededbecause Halon 1301, as a banned substance, is no longer manufactured andeventually the current supply will be depleted. There is a need,therefore, for new fire extinguishing compounds and fire extinguishingunits that contain them.

SUMMARY OF THE INVENTION

A first aspect of this invention is new compounds with fireextinguishing properties having the formula:

wherein R¹ is —CR⁵R⁶R⁷ or —CR⁵R⁶CR⁸R⁹R¹⁰;

R², R³ and R⁴ are each independently selected from halogen and hydrogen;and

R⁵, R⁶, R⁷, R⁸, R⁹ and R¹⁰ are each independently selected from halogenand hydrogen, wherein at least one of R⁵, R⁶, R⁷, R⁸, R⁹ and R¹⁰ ishalogen;

wherein when R¹ is —CR⁵R⁶CR⁸R⁹R¹⁰ and R⁸, R⁹ and R¹⁰ are each F, then atleast one of R², R³ and R⁴ is halogen;

wherein when R¹ is —CR⁵R⁶CR⁸R⁹R¹⁰ and R⁸, R⁹ and R¹⁰ are each F and whenR² is Br then one of R³ and R⁴ is halogen, or one of R⁵ and R⁶ ishydrogen;

wherein when R¹ is —CR⁵R⁶R⁷ and R⁵, R⁶, R⁷ are each F and R² is Br, thenR³ is halogen when R⁴ is selected from hydrogen or Br, or R³ is selectedfrom hydrogen, Cl, Br or I when R⁴ is F; and

wherein when R¹ is —CR⁵R⁶R⁷ and R⁵, R⁶, R⁷ are each F and R² is I, thenR³ is halogen when R⁴ is hydrogen, or R³ is selected from hydrogen, F,Cl and I when R⁴ is F.

In the above compounds: two or more substituents selected from R², R³and R⁴ may be halogen; R², R³ and R⁴ may each be halogen; and/or R², R³and R⁴ may each be independently selected from hydrogen, Br, Cl and I.

In the above compounds, R¹ may be —CR⁵R⁶R⁷ in which case R⁵, R⁶ and R⁷may each be halogen or R⁵, R⁶, and R⁷ may each be F.

In the above compounds, R¹ may be —CR⁵R⁶CR⁸R⁹R¹⁰ in which case R⁸, R⁹and R¹⁰ may each be halogen; or R⁸, R⁹, and R¹⁰ may each be F.

In the above compounds, R¹ may be —CR⁵R⁶CR⁸R⁹R¹⁰ in which case R⁵ and R⁶may each be halogen; or R⁵ and R⁶ may each be F.

In another aspect, the above compound may be 2-iodoperfluoro-1-butene;2,3-dibromo-4,4,4-trifluoro-1-butene; 2-iodoperfluoro-1-butene;2-bromoperfluoro-1-butene; 3-iodo-3,4,4,4-tetrafluoro-1-butene;1-iodo-4,4,4-trifluoro-1-butene; 2-bromo-3,3,4,4,4-pentafluoro-1-butene;1-bromo-4,4,4-trifluoro-1-butene;2-chloro-3,3,4,4,4-pentafluoro-1-butene; and isomers thereof.

Yet another aspect of this invention are fire extinguishing unitscomprising a container and delivery system, the container containing atleast one fire extinguishing compound having the formula:

wherein R¹ is —CR⁵R⁶R⁷ or —CR⁵R⁶CR⁸R⁹R¹⁰;

R², R³ and R⁴ are each independently selected from halogen or hydrogenwherein at least one of R², R³ and R⁴ must be halo; and

R⁵, R⁶, R⁷, R⁸, R⁹ and R¹⁰ are each independently selected from halogenor hydrogen wherein at least one of R⁵, R⁶, R⁷, R⁸, R⁹ and R¹⁰ must behalogen;

wherein when R¹ is —CR⁵R⁶CR⁸R⁹R¹⁰ and R⁸, R⁹ and R¹⁰ are each F, then atleast one of R³ and R⁴ is halogen when R² is hydrogen, or R² is Cl, F orI when R³ and R⁴ are both hydrogen; and

wherein when R¹ is —CR⁵R⁶R⁷ and R⁵, R⁶, R⁷ are each F then R², R³ and R⁴are each hydrogen or halogen, or when R² is Br then R³ is selected fromhalogen and R⁴ is selected from hydrogen, Cl, F and I.

In the above fire extinguishing unit, the fire extinguishing compoundmay include substituents R², R³ and R⁴ wherein two or more of thesubstituents are halogen; or where each substituent is halogen; or whereeach substituent is selected from hydrogen, Br, Cl and I.

In the above fire extinguishing unit, the fire extinguishing compoundincludes substituent R¹ that may be —CR⁵R⁶R⁷ in which case R⁵, R⁶, andR⁷ may each be halogen; or R⁵, R⁶, and R⁷ may each be F.

In the above fire extinguishing unit, the fire extinguishing compoundincludes substituent R¹ that may be —CR⁵R⁶CR⁸R⁹R¹⁰ in which case R⁸, R⁹,and R¹⁰ may each be halogen; or R⁸, R⁹, and R¹⁹ may each be F; or inwhich case R⁵ and R⁶ may each be halogen or may each be F.

In the above fire extinguishing unit, the fire extinguishing compoundmay be selected from 2-iodoperfluoro-1-butene;2,3-dibromo-4,4,4-trifluoro-1-butene; 2-iodoperfluoro-1-butene;2-bromoperfluoro-1-butene; 3-iodo-3,4,4,4-tetrafluoro-1-butene;1-iodo-4,4,4-trifluoro-1-butene; 2-bromo-3,3,4,4,4-pentafluoro-1-butene;1-bromo-4,4,4-trifluoro-1-butene;2-chloro-3,3,4,4,4-pentafluoro-1-butene;2-bromo-1,1,3,3,3-pentafluoropropene;2-iodo-1,1,3,3,3-pentafluoropropene; 2-iodo-3,3,3-trifluoropropene,isomers thereof and combinations thereof.

DESCRIPTION OF CURRENT EMBODIMENTS

The present invention relates to novel compounds that have fireretarding properties as well as fire extinguishing units that includeone or more fire retarding compounds. The compounds discussed below areall expected to have acceptable to very good abilities to extinguish aheptane flame—Heptane Cap Burner Value.

Useful fire extinguishing compounds have the general formula:

wherein R¹ is —CR⁵R⁶R⁷ or —CR⁵R⁶CR⁸R⁹R¹⁰;

R², R³ and R⁴ are each independently selected from halogen or hydrogenwherein at least one of R², R³ and R⁴ must be halo; and

R⁵, R⁶, R⁷, R⁸, R⁹ and R¹⁰ are each independently selected from halogenor hydrogen wherein at least one of R⁵, R⁶, R⁷, R⁸, R⁹ and R¹⁰ must behalogen;

wherein when R¹ is —CR⁵R⁶CR⁸R⁹R¹⁰ and R⁸, R⁹ and R¹⁰ are each F, then atleast one of R³ and R⁴ is halogen when R² is hydrogen, or R² is Cl, F orI when R³ and R⁴ are both hydrogen; and

wherein when R¹ is —CR⁵R⁶R⁷ and R⁵, R⁶, R⁷ are each F then R², R³ and R⁴are each hydrogen or halogen, or when R² is Br then R³ is selected fromhalogen and R⁴ is selected from hydrogen, Cl, F and I.

In this aspect, when R¹ is —CR⁵R⁶R⁷ or —CR⁵R⁶CR⁸R⁹R¹⁰ then two or moresubstituents selected from R², R³ and R⁴ may be halogen; or R², R³ andR⁴ may each be halogen; or R², R³ and R⁴ may each be independentlyselected from hydrogen, Br, Cl and I.

Alternatively, in this aspect, when R¹ is —CR⁵R⁶R⁷ then R⁵, R⁶, and R⁷may each be halogen and more narrowly R⁵, R⁶, and R⁷ may each be F.Moreover, when R¹ is —CR⁵R⁶R⁷ then the fire extinguishing compound ofthis invention may be selected from2-bromo-1,1,3,3,3-pentafluoropropene;2-iodo-1,1,3,3,3-pentafluoropropene; 2-iodo-3,3,3-trifluoropropene andcombinations thereof identified in Table 1 below.

In the aspect above, when R¹ is —CR⁵R⁶CR⁸R⁹R¹⁰ then R⁸, R⁹, and R¹⁰ mayeach be halogen and more narrowly, R⁸, R⁹, and R¹⁰ may each be F.Alternatively or in addition, when R¹ is —CR⁵R⁶CR⁸R⁹R¹⁰ then R⁵ and R⁶may each be halogen and more narrowly R⁵ and R⁶ may each be F. Finally,when R¹ is —CR⁵R⁶CR⁸R⁹R¹⁰ then the fire extinguishing compound of thisinvention may be selected from 2-iodoperfluoro-1-butene;2,3-dibromo-4,4,4-trifluoro-1-butene; 2-iodoperfluoro-1-butene;2-bromoperfluoro-1-butene; 3-iodo-3,4,4,4-tetrafluoro-1-butene;1-iodo-4,4,4-trifluoro-1-butene; 2-bromo-3,3,4,4,4-pentafluorobutene;2-chloro-3,3,4,4,4-pentafluoro-1-butene; isomers thereof andcombinations thereof as identified in Table 1 below.

TABLE 1 Compound Name Formula 2-bromo-1,1,3,3,3-pentafluoropropene

2-iodo-1,1,3,3,3-pentafluoropropene

2-iodo-3,3,3-trifluoropropene

1-bromo-4,4,4-trifluoro-1-butene

2,3-dibromo-4,4,4-trifluoro-1-butene

2-iodoperfluoro-1-butene

2-bromoperfluoro-1-butene

3-iodo-3,4,4,4-tetrafluoro-1-butene

1-iodo-4,4,4-trifluoro-1-butene

2-bromo-3,3,4,4,4-pentafluorobutene

2-chloro-3,3,4,4,4-pentafluoro-1-butene

In an alternative aspect, the fire extinguishing compounds have thegeneral Formula I above wherein R¹ is —CR⁵R⁶R⁷ or —CR⁵R⁶CR⁸R⁹R¹⁰;

R², R³ and R⁴ are each independently selected from halogen and hydrogen;and

R⁵, R⁶, R⁷, R⁸, R⁹ and R¹⁰ are each independently selected from halogenand hydrogen, wherein at least one of R⁵, R⁶, R⁷, R⁸, R⁹ and R¹⁰ ishalogen, and

wherein when R¹ is —CR⁵R⁶CR⁸R⁹R¹⁰ and R⁸, R⁹ and R¹⁰ are each F, then atleast one of R², R³ and R⁴ is halogen;

wherein when R¹ is —CR⁵R⁶CR⁸R⁹R¹⁰ and R⁸, R⁹ and R¹⁰ are each F and whenR² is Br then one of R³ and R⁴ is halogen, or one of R⁵ and R⁶ ishydrogen;

wherein when R¹ is —CR⁵R⁶R⁷ and R⁵, R⁶, R⁷ are each F and R² is Br, thenR³ is halogen when R⁴ is selected from hydrogen or Br, or R³ is selectedfrom hydrogen, Cl, Br or I when R⁴ is F; and

wherein when R¹ is —CR⁵R⁶R⁷ and R⁵, R⁶, R⁷ are each F and R² is I, thenR³ is halogen when R⁴ is hydrogen, or R³ is selected from hydrogen, F,Cl and I when R⁴ is F.

In this alternative aspect, when R¹ is —CR⁵R⁶R⁷ or —CR⁵R⁶CR⁸R⁹R¹⁰ thenR², R³ and R⁴ may each be halogen or R², R³ and R⁴ may each beindependently selected from hydrogen, Br, Cl and I. In anotheralternative, when R¹ is —CR⁵R⁶R⁷ then R⁵, R⁶, and R⁷ may each be halogenor R⁵, R⁶, and R⁷ may each be F.

Also in this alternative aspect, when R¹ is —CR⁵R⁶CR⁸R⁹R¹⁰ then R⁸, R⁹,and R¹⁰ may each be halogen or more narrowly R⁸, R⁹, and R¹⁰ may each beF. Moreover, when R¹ is —CR⁵R⁶CR⁸R⁹R¹⁰ then R⁵ and R⁶ may each behalogen and more narrowly R⁵ and R⁶ may each be each F.

Further in this alternative aspect, the compound is selected from 2-iodoperfluoro-1-butene; 2,3-dibromo-4,4,4-trifluoro-1-butene;2-bromoperfiuoro-1-butene; 3-iodo-3,4,4,4-tetrafluoro-1-butene;1-iodo-4,4,4-trifluoro-1-butene; 2-bromo-3,3,4,4,4-pentafluorobutene;1-bromo-4,4,4-trifluoro-1-butene;2-chloro-3,3,4,4,4-pentafluoro-1-butene; and isomers thereof asidentified in Table 1 above.

As used herein the term halogen is used in its normal and customarymanner to refer to chloro (Cl), fluoro (F), bromo (Br) and iodo

The fire extinguishing compounds identified above are useful alone orcombined with other fire extinguishing composition ingredients when usedin a fire extinguishing unit to suppress or extinguish fires. Firesuppression refers to a use of agents such as gases, liquids, solids,chemicals and mixtures thereof to extinguish combustion.

The fire extinguishing compounds discussed above are useful in fireextinguishing units that include various containers and delivery systemsthat may in turn be used in a variety of fire extinguishingapplications. Such units and delivery systems include, but are notlimited to hand-held fire extinguishing units, permanent fireextinguishing systems, modular fire extinguishing systems and the likewhich may be used in the home, computer rooms, kitchens, factorieswarehouse facilities, airplanes, cars, trucks, heavy-equipment, etc. Thefire extinguishing compound(s) may be used in units that are used inflood and streaming-type fire extinguishing applications. The compoundsmay be placed in any known container that is used to hold fireextinguishing compounds and compositions such as hand-held extinguishingcontainers, tanker trucks such as those associated with fire trucks,wheeled containers and the like.

Some fire suppression units or systems use a “total flooding” or a“non-total flooding” methods to apply an extinguishing agent in anenclosed volume. The total flooding or the non-total flooding method mayachieve a concentration of the extinguishing agent as a volume percentto air of the extinguishing agent sufficient to suppress or extinguish afire.

In aircraft applications, each cargo compartment may have its owndedicated distribution system comprising tubes routed to nozzles in acargo bay. The nozzles may be mounted in pans down a centerline of acargo bay ceiling liner. An extinguishing agent including one or more ofthe fire extinguishing compounds disclosed above may also be releaseddirectly into a compartment where there are no tubes or nozzles, as theagent container(s) is/are plugged directly into the compartment. Firesuppression systems may be operated automatically by an automaticdetection and control mechanism, and/or manually by manual activation ofan actuator via a local and/or remote switch, a combination thereof, andthe like.

Fire suppression units and delivery systems are generally sized forworst case scenarios that may occur during descent when an aircraftbegins to re-pressurize. Therefore, additional equipment and suppressantchemicals required during descent may determine a size of an overallsystem with resulting added weight and volume.

The useful fire extinguishing units include one or more of the abovefire extinguishing compounds and optionally include additional activeand inert fire suppression or extinguishing ingredients, Activeingredients might include, for example, oxygen depleting agents, heatremoving (endothermic) agents such as carbon dioxide, additional flameretarding or extinguishing agents and the like.

Fire suppression units, delivery systems and methods that can employ oneor more fire extinguishing compounds of this invention are well known.For example, U.S. Pat. No. 8,925,642 discloses a scalable cargo firesuppression agent distribution system. The system includes a pluralityof fire suppression agent supply source units. During use, a supplysource unit subset of the total source units is/are selected based on anoperation condition, and a fire suppression agent from the supply sourceunit subset is distributed during the operation condition. In thismanner, significantly less storage space and supply source containerweight is required to store fire suppression agents.

In another example, U.S. Pat. No. 7,510,022 is directed to firesuppression systems for aircraft cargo compartments. The firesuppression systems can include at least one fire-suppressant vessel, atleast one discharge conduit coupled to the at least one fire-suppressantvessel, and a valve arrangement coupled to the fire-suppressant vesseland the discharge conduit. The valve arrangement has multiple settingsthat allows for the control of the discharge rate of a fire suppressantheld in the vessels.

In yet another example, U.S. Pat. No. 4,726,426 discloses a firesuppression system for extinguishing fires in an aircraft passengercabin. The system uses the passenger cabin environmental control systemductwork to direct a fire suppression agent from a vessel or containerin the cargo hold into the passenger cabin. Other examples of firesuppression systems are within the knowledge of one skilled in the art.

EXAMPLE—COMPOUND SYNTHESIS METHODS

Fire retardant compounds of this invention can be prepared by thesynthesis methods detailed in this example. Moreover, the skilled personwould understand that there are other synthesis methods that can be usedto prepare the fire retardant compounds identified above.

Method A

These synthesis procedures use a (C₃HF₅O) aldehyde that is prepared byesterifying pentafluoropropionic acid with methanol and trace amount ofsulfuric acid. The ester, methyl pentafluoropropionate, is purified bydistillation. Next, the methyl pentafluoropropionate is reduced to2,2,3,3,3-pentafluoropropionaldehyde (C₃HF₅O) with a slight excess ofdi-isobutylaluminum hydride and purified by distillation.

-   -   (1) 2-iodoheptafluorobutene and 2-bromoheptafluorobutene are        synthesized using the (C₃HF₅O) aldehyde made above as follows:        -   (a) Perform a one-pot reaction using one equivalent of the            (C₃HF₅O) aldehyde, three equivalents of            (chlorodifluoromethyl)trimethyl silane and three equivalents            of triphenylphosphine in Tetrahydrofuran (“THF”) at 70° C.            for 10 hours. The “CF₂” equivalent converts the R(H)C═O from            the aldehyde to an R(H)C═CF₂ and the product is purified by            distillation.        -   i. 2-iodoheptafluorobutene is derived by abstracting            aldehyde hydrogen with one equivalent of n-butyl lithium in            THF at −78° C., warm, and quenching with iodine.        -   ii. 2-bromoheptafluorobutene is derived by abstracting            aldehyde hydrogen with one equivalent of n-butyl lithium in            THF at −78° C., warm, and quenching with bromine.    -   (2) 2-Chloro-3,3,4,4,4-pentafluorobutene is synthesized using        the (C₃HF₅O) aldehyde made above as follows:        -   a. Perform a one-pot reaction using one equivalent of the            (C₃HF₅O) aldehyde, three equivalents of            (chloromethyl)trimethyl silane and three equivalents of            triphenylphosphine in THF at 70° C. for 10 hours. The “CH₂”            equivalent converts the R(H)C═O from the aldehyde to an            alkene, e.g. R(H)C═CH₂. The resulting product is            3,3,4,4,4-pentafluoro-1-butene and it is purified by            distillation.        -   b. 2-Chloro-3,3,4,4,4-pentafluorobutene is derived by            abstracting aldehyde hydrogen with one equivalent of n-butyl            lithium in THE at −78° C., warming and then quenching with            aqueous chlorine.

Method B

1-lodo-4,4,4-trifluoro-1-butene and 1-bromo-4,4,4-trifluoro-1-butene aresynthesized as follows:

React propargyl chloride with one equivalent oftris(triphenylphosphine)copper trifluoromethane, (Ph₃P)3CuCF₃ to give4,4,4-trifluoro-1-butyne. Next, react 4,4,4-trifluoro-1-butyne withdibutylaluminum hydride in n-heptane solution at <40° C.) and then warmthe solution to 50° C.

a. 1-lodo-4,4,4-trifluorobutene is derived from the reaction productabove by cooling the solution to −50° C., and quenching with iodine togive a mixture of cis- and trans-1 -iodo-4,4,4-trifluoro-1-butene.

-   -   1-Bromo-4,4,4-trifluoro-1-butene is derived from the reaction        product above by using bromine instead of iodine in reaction        step (a) above to form a cold quench mixture of cis- and        trans-1-bromo-4,4,4-trifluoro-1-butene.

Method C

2,3-dibromo-4,4,4-trifluoro-1-butene is prepared by reacting2-bromo-4,4,4-trifluoro-1-butene with one equivalent of sodiumt-butoxide in t-butanol at low temperature (−78° C. to −40° C.) and thenquenching the solution slowly with bromine to yield the above-mentioneddibromo product.

2-bromo-4,4,4-trifluoro-1-butene is prepared by reacting2,3-dibromo-1-propene with one equivalent of(1,10-phenanthroline)(trifluoromethyl) copper

Method D

3,4,4,4-tetrafluoro-1-butene is prepared by reacting3-bromo-3-fluoro-1-propene with (1,10-phenanthroline)(trifluoromethyl)copper(I).

3,4,4,4-tetrafluoro-3-iodo-1-butene is prepared by reacting sodiumt-butoxide with 3,4,4,4-tetrafluoro-1-butene, followed by quenching withiodine.

The foregoing description of the specific embodiments will reveal thegeneral nature of the disclosure so others can, by applying currentknowledge, readily modify and/or adapt for various applications suchspecific embodiments without departing from the generic concept, andtherefore such adaptations and modifications are intended to becomprehended within the meaning and range of equivalents of thedisclosed embodiments. It is to be understood that the phraseology orterminology herein is for the purpose of description and not oflimitation.

What is claimed is:
 1. A compound having the formula:

wherein R¹ is —CR⁵R⁶R⁷ or —CR⁵R⁶CR⁸R⁹R¹⁰; R², R³ and R⁴ are eachindependently selected from halogen and hydrogen; and R⁵, R⁶, R⁷, R⁸, R⁹and R¹⁰ are each independently selected from halogen and hydrogen,wherein at least one of R⁵, R⁶, R⁷, R⁸, R⁹ and R¹⁰ is halogen, and:wherein when R¹ is —CR⁵R⁶CR⁸R⁹R¹⁰ and R⁸, R⁹ and R¹⁰ are each F, then atleast one of R², R³ and R⁴ is halogen; wherein when R¹ is —CR⁵R⁶CR⁸R⁹R¹⁰and R⁸, R⁹ and R¹⁰ are each F and when R² is Br then one of R³ and R⁴ ishalogen, or one of R⁵ and R⁶ is hydrogen; wherein when R¹ is —CR⁵R⁶R⁷and R⁵, R⁶, R⁷ are each F and R² is Br, then R³ is halogen when R⁴ isselected from hydrogen or Br, or R³ is selected from hydrogen, Cl, Br orI when R⁴ is F; and wherein when R¹ is —CR⁵R⁶R⁷ and R⁵, R⁶, R⁷ are eachF and R² is I, then R³ is halogen when R⁴ is hydrogen, or R³ is selectedfrom hydrogen, F, Cl and I when R⁴ is F.
 2. The compound of claim 1wherein two or more substituents selected from R², R³ and R⁴ arehalogen.
 3. The compound of claim 1 wherein R², R³ and R⁴ are eachhalogen.
 4. The compound of claim 1 wherein R², R³ and R⁴ are eachindependently selected from hydrogen, Br, Cl and I.
 5. The compound ofclaim 1 wherein R¹ is —CR⁵R⁶R⁷.
 6. The compound of claim 1 wherein R¹ is—CR⁵R⁶CR⁸R⁹R¹⁰.
 7. A method for extinguishing a fire, the methodcomprising directing a compound of claim 1 towards a fire.
 8. A fireextinguishing unit comprising a container and delivery system, thecontainer containing a fire extinguishing compound according to theformula:

wherein R¹ is —CR⁵R⁶R⁷ or —CR⁵R⁶CR⁸R⁹R¹⁰; R², R³ and R⁴ are eachindependently selected from halogen or hydrogen wherein at least one ofR², R³ and R⁴ must be halo; and R⁵, R⁶, R⁷, R⁸, R⁹ and R¹⁰ are eachindependently selected from halogen or hydrogen wherein at least one ofR⁵, R⁶, R⁷, R⁸, R⁹ and R¹⁰ must be halogen; wherein when R¹ is—CR⁵R⁶CR⁸R⁹R¹⁰ and R⁸, R⁹ and R¹⁰ are each F, then at least one of R³and R⁴ is halogen when R² is hydrogen, or R² is Cl, F or I when R³ andR⁴ are both hydrogen; and wherein when R¹ is —CR⁵R⁶R⁷ and R⁵, R⁶, R⁷ areeach F then R², R³ and R⁴ are each hydrogen or halogen, or when R² is Brthen R³ is selected from halogen and R⁴ is selected from hydrogen, Cl, Fand I.
 9. The fire extinguishing unit of claim 8 wherein two or moresubstituents are selected from R², R³ and R⁴ are halogen.
 10. A compoundhaving the formula:(F₃C)C(R⁵)(R⁶)C(R²)═CR³R⁴ wherein R⁵ and R⁶ are independently hydrogenor halogen; R² is chloro or iodo; and R³ and R⁴ are defined as follows:R³ is iodo and R⁴ is hydrogen; R³ and R⁴ are both fluoro; or R³ and R⁴are both hydrogen.
 11. A compound according to claim 10 wherein R³ isiodo and R⁴ is hydrogen.
 12. A compound according to claim 10 wherein R³and R⁴ are both fluoro.
 13. A compound according to claim 10 wherein R³and R⁴ are both hydrogen.
 14. A compound which is2,3-dibromo-4,4,4-trifluoro-1-butene; 2-iodoperfluoro-1-butene;2-bromoperfluoro-1-butene; 3-iodo-3,4,4,4-tetrafluoro-1-butene;1-iodo-4,4,4-trifluoro-1-butene; 1-bromo-4,4,4-trifluoro-1-butene; or2-chloro-3,3,4,4,4-pentafluoro-1-butene.